Method for Verifying Sound Amplitude Control Precision and Active Sound Generation System

Abstract

The present invention relates to the technical field of active sound generation systems for electric vehicles, and discloses a method for verifying the sound amplitude control accuracy of an active sound generation system for an electric vehicle and an active sound generation system. The method for verifying the sound amplitude control accuracy includes: determining the final sound scheme to be loaded into the active sound generation system of the electric vehicle to obtain the sound target of the active sound generation system; under the condition of a high-fidelity sound field restoration system, simulating the acceleration driving conditions at different accelerator pedal openings to verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the high-fidelity sound field restoration system, and verifying the achievement of the sound target of the active sound generation system under the acceleration driving conditions at 100% accelerator pedal opening; under the condition of the vehicle being stationary, simulating the acceleration driving conditions at different accelerator pedal openings to verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the vehicle being stationary, and verifying the achievement of the sound target of the active sound generation system under the acceleration driving conditions at 100% accelerator pedal opening.

Description

Technical Field

[0001] The present invention relates to the technical field of active sound generation systems for electric vehicles, and particularly to a method for verifying the sound amplitude control accuracy of an active sound generation system for an electric vehicle and an active sound generation system. Background Art

[0002] Electric vehicles have eliminated the powertrain systems of traditional vehicles such as engines and intake and exhaust systems, and added systems such as drive motors and power batteries. The sounds inside an electric vehicle are mainly motor noise, road noise, and wind noise. Among them, the frequency characteristics of motor noise show high-frequency characteristics, while road noise and wind noise show broadband random noise characteristics. Electric vehicles no longer have engine noise, which can effectively reduce the noise amplitude inside the vehicle. However, due to the lack of the masking effect of engine noise, the dynamic changes in the sounds inside the vehicle are characterized by the motor order sounds that change with the vehicle speed. The motor order sounds often consist of several pure tone components with relatively single high-frequency characteristics. Although the energy of these motor order components is not large, due to their high frequency and single-frequency pure tone characteristics, excessive amplitude will make people feel irritable and uncomfortable in terms of hearing.

[0003] Therefore, the influence of motor order sounds on the sound quality inside an electric vehicle is very significant, and NVH engineers are committed to controlling and even eliminating such sounds. In this development trend, the sounds inside electric vehicles of different brands will tend to be homogenized, without the recognition of sound quality characteristics. At the same time, the road noise and wind noise that change with the dynamic driving of the vehicle are not sufficient to provide effective feedback information to the driver. This lack of feedback information in terms of hearing will make the driver's control of the vehicle operation state not comprehensive enough, and is likely to cause certain deviations in the judgment of the vehicle driving state. Therefore, an active sound generation system is needed to simulate the feedback sounds that change dynamically with the vehicle inside an electric vehicle, similar to the engine order sounds inside an internal combustion engine vehicle, so that the driver can obtain good sound feedback. However, during the development and design process of the active sound generation system, there are many factors affecting the sound amplitude accuracy, and it is necessary to clarify the influence of each key link on the sound amplitude control accuracy.

[0004] Therefore, there is an urgent need for a method for verifying the sound amplitude control accuracy and an active sound generation system to solve the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for verifying the sound amplitude control accuracy and an active sound generation system, which can effectively separate the influence of the system's own circuit and the frequency response of the in-vehicle audio system on the sound amplitude control accuracy, and point out the direction for optimizing the sound amplitude control accuracy of the subsequent active sound generation system, thereby improving the work efficiency during the development process of the active sound generation system.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] On the one hand, a method for verifying the accuracy of sound amplitude control is provided, including the following steps:

[0008] Determine the final sound scheme to be loaded into the active sound system of the electric vehicle to obtain the sound target of the active sound system;

[0009] Under the condition of a high-fidelity sound field restoration system, simulate the acceleration driving conditions at different accelerator pedal openings, verify the accuracy of sound amplitude control and the accuracy of sound amplitude gain control under the condition of the high-fidelity sound field restoration system, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening;

[0010] Under the condition of the vehicle being stationary, simulate the acceleration driving conditions at different accelerator pedal openings, verify the accuracy of sound amplitude control and the accuracy of sound amplitude gain control under the condition of the vehicle being stationary, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening.

[0011] As a preferred scheme of a method for verifying the accuracy of sound amplitude control, conduct the in-vehicle sound design for the electric vehicle during acceleration, and determine the time-domain signal, spectrogram, and sound amplitude change curve of the final sound scheme to be loaded into the active sound system.

[0012] As a preferred scheme of a method for verifying the accuracy of sound amplitude control, perform discrete short-time Fourier transform analysis on the in-vehicle order sound signal corresponding to the final sound scheme, and extract the sound amplitude characteristic parameters and phase characteristic parameters in the frequency range of 20 - 1200 Hz.

[0013] As a preferred scheme of a method for verifying the accuracy of sound amplitude control, conduct discrete short-time Fourier transform synthesis according to the extracted amplitude characteristic parameters and phase characteristic parameters of the order component sound, fit the synthesized sound of the final sound scheme, evaluate the difference between the synthesized sound and the sound of the final scheme from the perspectives of objective spectrum analysis and subjective audition, and make appropriate parameter adjustments for the discrete short-time Fourier transform analysis for the difference situation, so that the synthesized sound fitted reaches the sound effect of the final scheme.

[0014] As a preferred scheme of a method for verifying the accuracy of sound amplitude control, in terms of vehicle speed, define the virtual engine speed, define the vehicle speed range of the active sound in the electric vehicle within 0 - 120 km / h, and according to the law that the engine speed of an internal combustion engine vehicle changes linearly with the vehicle speed at a certain fixed gear, the calculation formula for the virtual engine speed and vehicle speed of the active sound system can be obtained:

[0015] n V = A × V + n I

[0016] In the formula, n V is the virtual engine speed of the active sound generation system of the electric vehicle; A is the change amount of the virtual engine speed per unit vehicle speed, where: [(r / min) / (km / h)], where n R is the rated speed of the virtual engine, and n I is the idle speed of the virtual engine; V is the vehicle speed;

[0017] Import the calculation formula of the virtual engine speed and vehicle speed of the active sound generation system into the active sound generation system, so that the active sound generation system can calculate the virtual engine speed according to the vehicle speed.

[0018] As an optimal solution of a method for verifying the sound amplitude control accuracy, in terms of the accelerator pedal opening, obtain the first curve of the sound amplitude gain of the active sound generation system of the electric vehicle changing with the accelerator pedal opening, and import the parameters of the first curve into the active sound generation system, so that the active system can control the sound amplitude gain of the active sound generation system according to the change of the accelerator pedal opening.

[0019] As an optimal solution of a method for verifying the sound amplitude control accuracy, construct a high-fidelity sound field restoration system through several high-fidelity speakers to restore the in-vehicle sound field environment of the electric vehicle, adjust the mutual relationships such as amplitude and delay between each speaker to ensure that a high-amplitude and flat and consistent frequency response can be obtained within the frequency range of the sound generated by the active sound generation system at the target receiving point; connect the active sound generation control system to the high-fidelity sound field restoration system, and in the environment of the vehicle half-anechoic chamber, control the active sound generation system to emit a white noise signal through the high-fidelity sound field restoration system, and test the sound response at the target receiving point to verify the actual frequency response of the high-fidelity sound field restoration system at the target receiving point position.

[0020] As an optimal solution of a method for verifying the sound amplitude control accuracy, connect the active sound generation control system to the vehicle so that the system can normally read information such as vehicle speed, motor speed, and accelerator pedal opening position during operation; on the basis of the speakers of the original vehicle audio system of the electric vehicle, build an active sound generation system of the electric vehicle, and play the sound generated by the active sound generation system through the audio system; in the environment of the vehicle half-anechoic chamber, control the active sound generation system to emit a white noise signal through the in-vehicle audio system, and test the sound response at the target receiving point to verify the actual frequency response at the target receiving point position under the condition of the vehicle being stationary.

[0021] On the other hand, an active sound generation system is provided, including the method for verifying the sound amplitude control accuracy as described above.

[0022] Advantages of the present invention:

[0023] In order to better verify the sound amplitude control accuracy of the active sound generation system for electric vehicles, the technical solution of the present invention verifies the sound amplitude control accuracy of the active sound generation system from two aspects of the change in the total sound value and the sound amplitude gain control respectively under the conditions of a high-fidelity sound field restoration system and the static condition of the in-vehicle audio system. It can effectively separate the influence of the system's own circuit and the frequency response of the in-vehicle audio system on the sound amplitude control accuracy, thereby clarifying the influence mechanism of the control system and the frequency response of the in-vehicle audio system on the sound amplitude control effect of the active sound generation system, pointing out the direction for the optimization of the sound amplitude control accuracy of the subsequent active sound generation system, and thus improving the work efficiency in the development process of the active sound generation system. Description of the drawings

[0024] Figure 1 is a schematic diagram of the time-domain signal of the final solution for the accelerating sound of the active sound generation system provided by the present invention;

[0025] Figure 2 is a spectrogram of the final solution for the accelerating sound of the active sound generation system provided by the present invention;

[0026] Figure 3 is a schematic diagram of the sound amplitude change curve of the final solution for the accelerating sound of the active sound generation system provided by the present invention;

[0027] Figure 4 is a schematic diagram of the relationship curve between the virtual engine speed and the vehicle speed provided by the present invention;

[0028] Figure 5 is a first schematic diagram of the change of the sound amplitude gain of the active sound generation system with the accelerator pedal opening provided by the present invention;

[0029] Figure 6 is an FFT spectrogram of the original white noise signal provided by the present invention;

[0030] Figure 7 is an FFT spectrogram of the white noise signal for the position test of the target receiving point of the high-fidelity sound field restoration system provided by the present invention;

[0031] Figure 8 is a schematic diagram of the change curve of the sound amplitude of the active sound generation system with the virtual engine speed at each accelerator pedal opening provided by the present invention;

[0032] Figure 9It is a schematic diagram of the sound test results of the simulated acceleration driving active sound system at 100% accelerator pedal opening under the condition of the high-fidelity sound field restoration system provided by the present invention;

[0033] Figure 10 It is a schematic diagram of the change curve of the sound amplitude gain of the active sound system with the accelerator pedal opening under the condition of the high-fidelity sound field restoration system provided by the present invention;

[0034] Figure 11 It is the FFT spectrum diagram of the frequency response of the audio system tested at the position of the driver's right ear in the vehicle provided by the present invention;

[0035] Figure 12 It is a schematic diagram of the change curve of the sound amplitude of the active sound system with the virtual engine speed at each accelerator pedal opening under the static condition of the in-vehicle audio system provided by the present invention;

[0036] Figure 13 It is a schematic diagram of the comparison of the change curves of the sound amplitude of the active sound system during simulated acceleration driving at 100% accelerator pedal opening under the static condition of the in-vehicle audio system provided by the present invention;

[0037] Figure 14 It is a schematic diagram of the change curve of the sound amplitude gain of the active sound system with the accelerator pedal opening under the static condition of the in-vehicle audio system provided by the present invention. Detailed implementation manners

[0038] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0040] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the present invention. In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0042] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "arranged" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over", and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under", and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0044] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation on the present invention.

[0045] Embodiment 1

[0046] This embodiment discloses a method for verifying the accuracy of sound amplitude control, which includes the following steps:

[0047] Determine the final sound scheme to be loaded into the active sound system of the electric vehicle to obtain the sound target of the active sound system;

[0048] Under the condition of a high-fidelity sound field restoration system, simulate the accelerating driving conditions at different accelerator pedal openings, verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the high-fidelity sound field restoration system, and at the same time verify the achievement of the sound target of the active sound system under the accelerating driving condition with 100% accelerator pedal opening;

[0049] Under the condition of the vehicle being stationary, simulate the accelerating driving conditions at different accelerator pedal openings, verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the vehicle being stationary, and at the same time verify the achievement of the sound target of the active sound system under the accelerating driving condition with 100% accelerator pedal opening.

[0050] Under the condition of the high-fidelity sound field restoration system and the static condition of the vehicle audio system respectively, verify the sound amplitude control accuracy of the active sound system from two aspects of the change in the total sound value and the sound amplitude gain control, which can effectively separate the influence of the system's own circuit and the frequency response of the vehicle audio system on the sound amplitude control accuracy, so as to clarify the influence mechanism of the control system and the frequency response of the vehicle audio system on the sound amplitude control effect of the active sound system, point out the direction for the subsequent optimization of the sound amplitude control accuracy of the active sound system, and thus improve the work efficiency in the development process of the active sound system.

[0051] Embodiment 2

[0052] The design of the active sound system for electric vehicles is very systematic and complex, involving many influencing factors, including sound scheme design and synthesis, selection and control of key parameters, development of software and hardware systems, frequency response of in-vehicle audio systems, etc. Each link will have an important impact on the final sound effect of the active sound system. Therefore, how to verify the sound amplitude control accuracy of the active sound system for electric vehicles and how to effectively decompose the influence of each key link on the sound amplitude control accuracy have become very important core technologies of the active sound system, which will directly affect the actual sound effect of the active sound system felt by the driver during actual vehicle driving.

[0053] This embodiment discloses a method for verifying the sound amplitude control accuracy, which includes the following steps:

[0054] The first step is the development and performance testing of the active sound system for electric vehicles.

[0055] In terms of hardware, the hardware control module and the main control circuit of the electric vehicle active sound system are designed. The main modules include: MCU calculation module, sound file storage module, CAN communication module, D / A digital-to-analog conversion module, audio output and power amplifier adjustment module, power supply module, etc. On this basis, appropriate hardware chips are selected for each module, including MCU chips, RAM memory chips, FLASH memory chips, audio D / A conversion chips, CAN assembly transceiver chips, power supply chips, and power amplifier modules, and the hardware circuit is designed, including the functional circuits of each chip, current detection circuit, high and low voltage detection circuit, and audio output circuit, etc. Then, the power supply voltage test of the main chips, CAN signal test, and audio signal test are carried out to confirm that the test results of each test item meet the design requirements.

[0056] In terms of software, the control software of the electric vehicle active sound system is written, and the software program is modularly designed, mainly divided into the following modules: chip initialization module, CAN signal data acquisition and processing module, FLASH sound data reading and preprocessing module, sound real-time calculation and output module, etc.

[0057] The second step is to extract and import the sound frequency characteristic parameters of the electric vehicle active sound system.

[0058] For the sound frequency characteristic parameter extraction and import of the electric vehicle active sound system, the in-vehicle sound design during the acceleration of the electric vehicle is carried out to determine the time-domain signal, spectrogram, and sound amplitude change curve of the final sound scheme that needs to be loaded into the active sound system. In this embodiment, the time-domain signal, spectrogram, and sound amplitude change curve of the final sound scheme for the acceleration driving sound design of the active sound system are as Figure 1 、 2 and shown in Figure 3.

[0059] For the spectrogram of the final sound scheme for the acceleration driving sound of the active sound system, the main integer-order and half-order components of the engine within the frequency range of 20 - 1200 Hz (the minimum order interval is 0.5 order) are extracted to obtain the spectrogram cloud map of the in-vehicle engine order sound under the acceleration driving condition. Then, through the short-time discrete Fourier transform, the sound signal of the in-vehicle engine order components under the acceleration driving condition is comprehensively obtained.

[0060] For the in-vehicle order sound signal corresponding to the final sound scheme during acceleration driving, discrete short-time Fourier transform analysis based on a certain window function (such as Kaiser window, Hanning window, Hamming window, etc.) is carried out. Within the frequency range of 20 - 1200 Hz, a series of sound amplitude characteristic parameters and phase characteristic parameters corresponding to each order sound component within a certain short time period with a certain time resolution (with 0.5 order as the minimum order interval) are extracted.

[0061] Based on the extracted amplitude characteristic parameters and phase characteristic parameters of the order component sound, perform discrete short-time Fourier transform synthesis to fit the synthesized sound of the final sound scheme. Evaluate the difference between the synthesized sound and the sound of the final scheme from the perspectives of objective spectrum analysis and subjective audition, and make appropriate parameter adjustments for the discrete short-time Fourier transform analysis according to the difference situation, so that the synthesized sound fitted reaches the sound effect of the final scheme.

[0062] Import the amplitude characteristic parameters and phase characteristic parameters of each order component sound after adjustment and optimization into the FLASH sound data reading and preprocessing module of the active sound system to prepare for the subsequent fitting of the sound inside the vehicle during the accelerated driving of the active sound system.

[0063] The third step: Extraction and import of the sound control characteristic parameters of the electric vehicle active sound system.

[0064] Use the vehicle speed and the opening of the accelerator pedal as the sound control parameters of the active sound system. In terms of vehicle speed, define the virtual engine speed. Define the vehicle speed range of the active sound inside the electric vehicle within 0 - 120 km / h. Among them, when the vehicle speed is 0 km / h, the virtual engine speed corresponding to the active sound system is 750 r / min, and when the vehicle speed is 120 km / h, the virtual engine speed is 6000 r / min. According to the law that the engine speed of an internal combustion engine vehicle changes linearly with the vehicle speed at a certain fixed gear, the calculation formula for the virtual engine speed and vehicle speed of the active sound system can be obtained:

[0065] n V = A×V + n I ……(1)

[0066] In the formula, n V is the virtual engine speed of the electric vehicle active sound system; A is the change amount of the virtual engine speed per unit vehicle speed, where: [(r / min) / (km / h)], where, n R is the rated speed of the virtual engine, n I is the idle speed of the virtual engine; V is the vehicle speed. According to formula (1), obtain the change curve of the relationship between the virtual engine speed and the vehicle speed, as Figure 4 shown. Import the calculation formula of the virtual engine speed and vehicle speed of the active sound system into the active sound system, so that the active sound system can calculate the virtual engine speed according to the vehicle speed.

[0067] In terms of the accelerator pedal opening, obtain the first curve of the sound amplitude gain of the electric vehicle active sound system varying with the accelerator pedal opening, and import the parameters of the first curve into the active sound system, so that the active system can control the sound amplitude gain of the active sound system according to the change of the accelerator pedal opening. Among them, the sound amplitude gain of the electric vehicle active sound system has a linear variation relationship with the accelerator pedal opening.

[0068] S1. For an internal combustion engine vehicle, obtain the first change curve of the in-vehicle engine order sound amplitude varying with the accelerator pedal opening and the second change curve of the engine output power varying with the accelerator pedal opening at different engine speeds.

[0069] S2. Define the engine output power load ratio as the ratio of the engine output power at a certain engine speed and a certain accelerator pedal opening to the engine output power at 100% accelerator pedal opening, calculate the third change curve of the in-vehicle engine order sound amplitude trend varying with the engine output power load ratio at different engine speeds, and obtain that the in-vehicle engine order sound amplitude has a linear relationship with the engine output power load ratio.

[0070] S3. For an electric vehicle, obtain the fourth change curve of the motor output power varying with the accelerator pedal opening at different motor speeds, obtain the linear change distribution diagram of the motor output power varying with the accelerator pedal opening, and obtain that in the non-rapid acceleration state, the motor output power has a linear relationship with the accelerator pedal opening.

[0071] S4. It is known from step S2 that the engine output power of the internal combustion engine vehicle has a linear relationship with the engine output power load ratio, and it is known from step S3 that the motor output power of the electric vehicle has a linear relationship with the accelerator pedal opening. Therefore, the accelerator pedal opening of the electric vehicle can be equivalent to the engine output power load ratio of the internal combustion engine vehicle. It is known from step S3 that the in-vehicle engine order sound amplitude has a linear relationship with the engine output power load ratio. Therefore, the sound amplitude gain of the electric vehicle active sound system has a linear variation relationship with the accelerator pedal opening.

[0072] In this embodiment, the target control curve of the sound amplitude gain of the active sound system varying with the accelerator pedal opening is shown in Figure 5. The sound amplitude gain coefficient α = 8.5 [dB(A) / 100%]. When the accelerator pedal opening is 0%, the sound amplitude gain is -8.5 dB(A). When the accelerator pedal opening is 100%, the sound amplitude gain is 0 dB(A). That is, when the vehicle accelerates at 100% accelerator pedal opening, the sound amplitude of the active sound system remains the sound amplitude of the system under the current working condition. When the vehicle accelerates at an accelerator pedal opening lower than 100%, the sound amplitude of the active sound system is corrected accordingly according to the size of the corresponding accelerator pedal opening and the sound amplitude gain control curve.

[0073] Step 4: Build the active sound system of the electric vehicle under the condition of the high-fidelity sound field restoration system.

[0074] Construct a high-fidelity sound field restoration system through a number of high-fidelity speakers to restore the sound field environment inside the electric vehicle, and adjust the mutual relationships such as amplitude and delay between each speaker to ensure that a high-amplitude and flat and consistent frequency response can be obtained within the frequency range of the sound generated by the active sound system at a preset target receiving point, where the preset target receiving point represents the positions near the ears of the driver's head of the electric vehicle. Connect the active sound control system properly with the high-fidelity sound field restoration system. Under the environment of the vehicle's semi-anechoic chamber, control the active sound system to emit a white noise signal through the high-fidelity sound field restoration system, and test the sound response at the target receiving point to verify the actual frequency response of the high-fidelity sound field reproduction and restoration system at the target receiving point position. The spectrum of the original white noise signal is as Figure 6 shown, and the sound spectrum obtained by testing at the target receiving point position is as Figure 7 shown.

[0075] Step 5: Verify and evaluate the sound amplitude accuracy of the active sound system of the electric vehicle under the condition of the high-fidelity sound field restoration system.

[0076] Under the condition of the high-fidelity sound field restoration system, simulate the acceleration driving conditions at different accelerator pedal openings (such as 20%, 30%, ……, 80%, 90%, 100%), verify the control accuracy of the sound amplitude and the control accuracy of the sound amplitude gain under the condition of the high-fidelity sound field restoration system, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening. If there is an error, correct the error to make the control accuracy of the sound amplitude and the control accuracy of the sound amplitude gain under the condition of the high-fidelity sound field restoration system basically coincide with the target setting value, and the sound target of the active sound system basically reaches the set value.

[0077] More specifically, the main parameters of the active sound system are set as follows:

[0078] ① Simulate the acceleration condition with the virtual engine speed accelerating from 1000 r / min to 6000 r / min;

[0079] ② Set the virtual accelerator pedal openings to: 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%;

[0080] ③ Set the gain curve of the accelerator pedal opening to Figure 5The curve, that is, the sound amplitude gain at 20% opening is (-8.5)×80% = (-6.8) dB(A), and the sound amplitude gain at 100% opening is 0 dB(A).

[0081] ④ Adjust the power amplifier of the high-fidelity sound field restoration system so that the sound amplitude at 100% opening is consistent with the total sound value of the final solution in Figure 1.

[0082] Under the condition of the high-fidelity sound field restoration system, simulate the acceleration driving conditions at each accelerator pedal opening, test the sound signals of the active sound generation system at each accelerator pedal opening at the target receiving point position, and obtain the comparative change curve of the acceleration driving sound amplitude at each accelerator pedal opening, as Figure 8 shown, where the acceleration driving sound amplitude change curve at 100% accelerator pedal opening is compared with Figure 3 as Figure 9 shown, verify the control accuracy of the acceleration driving sound amplitude at 100% accelerator pedal opening. It can be seen that there are slight differences in the rotational speed range of 4500 - 5300 r / min, and there is an error of 1.4 dB(A) in the sound amplitude compared with the designed state near 4900 r / min.

[0083] The sixth step is to build the active sound generation system of the electric vehicle and test the frequency response under the condition of the vehicle being stationary.

[0084] Connect the CAN communication module of the active sound generation control system to the vehicle's CAN BUS to ensure that the system can normally read information such as vehicle speed, motor speed, and accelerator pedal opening position during operation; take certain technical measures to enable the sound signal generated by the active sound generation module to be normally played through the vehicle's audio system. The main technical measures are: develop a separate active sound generation system controller and access it to the audio system power amplifier through the A2B bus; implant the active sound generation control algorithm into the entertainment system host and borrow the hardware resources of the host system for sound operation and synthesis, and output the sound signal to the audio system power amplifier through the A2B bus; integrate the active sound generation control module into the audio power amplifier and directly play the sound through the audio system. In this embodiment, based on the speakers of the original vehicle audio system of the electric vehicle, build the active sound generation system of the electric vehicle and play the sound generated by the active sound generation system through the audio system.

[0085] Under the environment of the vehicle's semi-anechoic chamber, control the active sound generation system to emit white noise signals through the vehicle's audio system, and test the sound response at the target receiving point to verify the actual frequency response at the target receiving point position under the condition of the vehicle being stationary. The target receiving point is specifically near the position of the driver's right ear. The spectrum of the original white noise signal is as Figure 5 shown, and the sound spectrum obtained by testing near the position of the driver's right ear is as Figure 11As shown, there is a relatively obvious sound transmission loss near 300 Hz and in the range of 480 - 600 Hz. There is also a certain sound transmission loss in the range of 600 - 800 Hz. At the same time, the sound amplitude in the frequency range below 100 Hz is significantly higher than that in other frequency bands.

[0086] Step 7: Verification of the sound amplitude control accuracy of the electric vehicle active sound system under static conditions of the production vehicle audio system.

[0087] Based on the parameters of the active sound system set in Step 5, perform an acceleration driving operation at 100% accelerator pedal opening under static conditions of the production vehicle audio system, test the sound signal at the position of the driver's right ear, and verify the sound amplitude control accuracy of the active sound system under static conditions of the production vehicle. The main parameter settings of the active sound system are the same as those in Step 5.

[0088] Under static conditions of the production vehicle, simulate the acceleration driving conditions at different accelerator pedal openings, verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under static conditions of the production vehicle, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening. Specifically, control the active sound system to simulate the acceleration driving conditions at each accelerator pedal opening, test the sound signal near the position of the driver's right ear inside the vehicle. The main parameter settings of the active sound system are as follows:

[0089] ① Simulate the acceleration condition with the virtual engine speed accelerating from 1000 r / min to 6000 r / min;

[0090] ② The virtual accelerator pedal openings are respectively set to: 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%;

[0091] ③ The acceleration pedal opening gain curve is set to Figure 1 the curve, that is, the sound amplitude gain at 20% opening is (-8.5)×80% = (-6.8) dB(A), and the sound amplitude gain at 100% opening is 0 dB(A).

[0092] ④ Adjust the power amplifier of the active sound system so that the sound amplitude at the position of the driver's right ear during acceleration driving at 100% opening is consistent with the total sound value of the final solution in Step 1.

[0093] Under static conditions of the production vehicle, simulate the acceleration driving conditions at each accelerator pedal opening, test the sound signal of the active sound system at each accelerator pedal opening at the position of the driver's right ear, and obtain the comparative change curve of the sound amplitude during acceleration driving at each accelerator pedal opening, as Figure 12 shown. Among them, compare the sound amplitude change curve during acceleration driving at 100% accelerator pedal opening withFigure 9 For comparison, such as Figure 13 shown. To verify the control accuracy of the sound amplitude during acceleration with the accelerator pedal fully opened under the condition of the vehicle's audio system, it can be seen that: the curve of the sound amplitude change emitted by the audio system is generally consistent with the verification result curve of the high-fidelity speaker. However, in the virtual engine speed range near 3000 r / min and within 2000 r / min, there is a large gap compared with the latter. The error between the test result of the original vehicle audio system and the verification result of the high-fidelity speaker does not exceed 10 dB(A). The main reason for the large error in the low-speed range is that the audio system enhances the sound amplitude within the 200 Hz frequency range, as Figure 11 shown.

[0094] Immediately afterwards, the verification of the sound amplitude gain control accuracy of the active sound system under the condition of the vehicle being stationary is carried out. Based on the sound amplitude during acceleration with the accelerator pedal fully opened, the differences in the sound amplitude during acceleration at other accelerator pedal openings are calculated respectively, and the control curve of the sound amplitude gain of the active sound system with the accelerator pedal opening is inversely calculated at typical virtual engine speeds (1000 r / min, 2000 r / min, 3000 r / min, 4000 r / min, 5000 r / min, 6000 r / min), and compared with Figure 10 For comparison, such as Figure 14 shown. It can be obtained that the sound amplitude generally shows a roughly linear increasing trend with the increase of the accelerator pedal opening at each speed. However, the amplitude gain curve at 1000 r / min fluctuates greatly, and the error between the sound amplitude gain and the set gain curve does not exceed 3 dB(A), mainly due to the non-uniformity of the frequency response of the original vehicle audio system in the entire frequency range.

[0095] Under the conditions of the high-fidelity sound field restoration system and the static condition of the vehicle's audio system respectively, the verification of the sound amplitude control accuracy of the active sound system is carried out from two aspects: the change of the total sound value and the control of the sound amplitude gain. It can effectively separate the influence of the system's own circuit and the frequency response of the vehicle's audio system on the sound amplitude control accuracy, thereby clarifying the influence mechanism of the control system and the frequency response of the vehicle's audio system on the sound amplitude control effect of the active sound system, pointing out the direction for the subsequent optimization of the sound amplitude control accuracy of the active sound system, and thus improving the work efficiency in the development process of the active sound system.

[0096] This embodiment also discloses an active sound system, which has the above-mentioned method for verifying the sound amplitude control accuracy.

[0097] The active sound generation system verifies the sound amplitude control accuracy of the active sound generation system from two aspects: the change in the total sound value and the control of the sound amplitude gain, under the conditions of a high-fidelity sound field restoration system and the static condition of the vehicle audio system. It can effectively separate the influence of the system's own circuit and the frequency response of the vehicle audio system on the sound amplitude control accuracy, thereby clarifying the influence mechanism of the control system and the frequency response of the vehicle audio system on the sound amplitude control effect of the active sound generation system, pointing out the direction for the subsequent optimization of the sound amplitude control accuracy of the active sound generation system, and thus improving the work efficiency in the development process of the active sound generation system.

[0098] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A method for verifying the accuracy of sound amplitude control, characterized in that, It includes the following steps: Determine the final sound scheme to be loaded into the active sound system of the electric vehicle to obtain the sound target of the active sound system; Under the condition of the high-fidelity sound field restoration system, simulate the acceleration driving conditions at different accelerator pedal openings, verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the high-fidelity sound field restoration system, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening; Under the condition of the stationary vehicle, simulate the acceleration driving conditions at different accelerator pedal openings, verify the sound amplitude control accuracy and the sound amplitude gain control accuracy under the condition of the stationary vehicle, and at the same time verify the achievement of the sound target of the active sound system under the acceleration driving condition at 100% accelerator pedal opening.

2. The method for verifying the sound amplitude control accuracy according to claim 1, characterized in that Conduct the in-vehicle sound design for the electric vehicle during acceleration driving, and determine the time-domain signal, spectrogram, and sound amplitude change curve of the final sound scheme to be loaded into the active sound system.

3. The method for verifying the sound amplitude control accuracy according to claim 2, wherein Perform discrete short-time Fourier transform analysis on the in-vehicle order sound signal corresponding to the final sound scheme, and extract the sound amplitude characteristic parameters and phase characteristic parameters in the frequency range of 20 - 1200 Hz.

4. The method for verifying the sound amplitude control accuracy according to claim 3, wherein Conduct discrete short-time Fourier transform synthesis based on the extracted amplitude characteristic parameters and phase characteristic parameters of the order component sound, fit the synthesized sound of the final sound scheme, evaluate the difference between the synthesized sound and the sound of the final scheme from the perspectives of objective spectrum analysis and subjective audition, and make appropriate parameter adjustments for the discrete short-time Fourier transform analysis according to the difference situation, so that the synthesized sound obtained by fitting achieves the sound effect of the final scheme.

5. The method for verifying the sound amplitude control accuracy according to claim 4, characterized in that In terms of vehicle speed, define the virtual engine speed. Define the vehicle speed range of the active sound in the electric vehicle within the range of 0 - 120 km / h. According to the law that the engine speed of an internal combustion engine vehicle changes linearly with the vehicle speed at a certain fixed gear, the calculation formula for the virtual engine speed of the active sound system and the vehicle speed can be obtained: n V = A × V + n I Where n V is the virtual engine speed of the electric vehicle active sound system; A is the change in the virtual engine speed corresponding to the unit vehicle speed, where: [(r / min) / (km / h)], where n R is the rated speed of the virtual engine, and n I is the idle speed of the virtual engine; V is the vehicle speed; Import the calculation formula for the virtual engine speed of the active sound system and the vehicle speed into the active sound system, so that the active sound system can calculate the virtual engine speed according to the vehicle speed.

6. The method for verifying the sound amplitude control accuracy according to claim 5, characterized in that In terms of the accelerator pedal opening, obtain the first curve of the sound amplitude gain of the active sound system of the electric vehicle changing with the accelerator pedal opening, and import the parameters of the first curve into the active sound system, so that the active system can control the sound amplitude gain of the active sound system according to the change of the accelerator pedal opening.

7. The method for verifying the sound amplitude control accuracy according to claim 6, wherein Construct a high-fidelity sound field restoration system through several high-fidelity speakers to restore the in-vehicle sound field environment of the electric vehicle, and adjust the mutual relationship of the amplitude and delay between each speaker to ensure that a high-amplitude and flat and consistent frequency response can be obtained within the frequency range of the sound generated by the active sound system at the target receiving point; Connect the active sound control system to the high-fidelity sound field restoration system. In the semi-anechoic chamber environment of the whole vehicle, control the active sound system to emit white noise signals through the high-fidelity sound field restoration system, and test the sound response at the target receiving point to verify the actual frequency response of the high-fidelity sound field restoration system at the target receiving point position.

8. The method for verifying the sound amplitude control accuracy according to claim 7, characterized in that Connect the active sound control system to the whole vehicle so that the system can normally read the information of vehicle speed, motor speed, and accelerator pedal opening position during operation; based on the speakers of the original vehicle audio system of the electric vehicle, build an active sound system for the electric vehicle and play the sound generated by the active sound system through the audio system. Under the environment of the whole vehicle semi-anechoic chamber, control the active sound system to emit white noise signals through the in-vehicle audio system and test the sound response at the target receiving point to verify the actual frequency response at the target receiving point position under the condition of the vehicle being stationary.

9. An active sound generation system, characterized in that, It includes the method for verifying the sound amplitude control accuracy as described in any one of claims 1-8.

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